Package com.isomorphic.base

# Class Config

java.lang.Object
org.apache.commons.collections4.map.AbstractIterableMap<K,V>
com.isomorphic.collections.DataTypeMap
com.isomorphic.base.Config

All Implemented Interfaces:
  `Map`, `org.apache.commons.collections4.Get`, `org.apache.commons.collections4.IterableGet`, `org.apache.commons.collections4.IterableMap`, `org.apache.commons.collections4.Put`

public class Config extends com.isomorphic.collections.DataTypeMap
This class provides config parameters to all the Java classes in the SmartClient Framework by reading a series of .properties files including server.properties.

If running in a servlets environment, you must use the "Init" servlet and use <load-on-startup> to ensure it initializes before any calls are made to this class.

Then the Config class can be used to read settings as follows:

     Config config = Config.getGlobal();
     String propertyValue = (String)config.getProperty("propertyName");

If running outside of a servlet environment, the following call should be made from the startup thread of the application before any Config APIs are called:

     Config.initGlobalConfig();

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static Config`
  `getGlobal()`
  Returns the global Config object, initializing it if it has not yet been set up.
  `static Config`
  `getGlobal(boolean initIfNull)`
  Returns the global Config object, optionally initializing it if it has not yet been set up.
  `static Object`
  `getProperty(String propertyName)`
  Returns a property extracted from the SmartClient global configuration file, server.properties.
  `static Config`
  `initGlobalConfig()`
  Initializes the global Config using the default Isomorphic ConfigLoader and ConfigParser, which read `.properties` files with variable interpolation.
  `Object`
  `put(Object key, Object value)`
  Programmatically inject a value into the global config.
  `void`
  `putAll(Map map)`
  Programmatically inject a set of values in a Map into the global config.

- ## Method Details

  - ### getGlobal

    public static Config getGlobal(boolean initIfNull)
    Returns the global Config object, optionally initializing it if it has not yet been set up.

    In a servlet environment, the Init servlet handles initialization automatically. In a non-servlet environment, call `initGlobalConfig()` from the startup thread before calling this method.

    Parameters:
      `initIfNull` - if true, automatically calls `initGlobalConfig()` when the global config has not yet been initialized
    Returns:
      the global Config instance, or null if `initIfNull` is false and the config has not been initialized

  - ### getGlobal

    public static Config getGlobal()
    Returns the global Config object, initializing it if it has not yet been set up. Equivalent to calling `getGlobal(true)`.

    See the `class overview` for usage examples.

    Returns:
      the global Config instance

  - ### getProperty

    public static Object getProperty(String propertyName)
    Returns a property extracted from the SmartClient global configuration file, server.properties. Note that the Init servlet must be used if you wish to make use of this API.
    Parameters:
      `propertyName` - The name of the property to retrieve
    Returns:
      The property value, or null if it was not found

  - ### initGlobalConfig

    public static Config initGlobalConfig() throws Exception
    Initializes the global Config using the default Isomorphic ConfigLoader and ConfigParser, which read `.properties` files with variable interpolation.

    In a servlet environment, the Init servlet calls this automatically. In a non-servlet environment, call this from the startup thread before any Config APIs are used, as shown in the `class overview`.

    Returns:
      the initialized global Config instance
    Throws:
      `Exception` - if the configuration cannot be loaded

  - ### put

    public Object put(Object key, Object value)
    Programmatically inject a value into the global config. Note, the timing of this is key. Your programmatic overrides or additions must take place after the core config has loaded from the framework's various `.properties` files, but before anything else in the system.

    The simplest way to achieve this is to have your programmatic changes to config invoked from a servlet which is configured in `web.xml` with a `load-on-startup` parameter of 2, like this:

         <servlet>
             <servlet-name>MyConfigChanges</servlet-name>
             <servlet-class>com.company.servlet.MyConfigChanges</servlet-class>
             <load-on-startup>2</load-on-startup>
         </servlet>

    The setting of "2" is important, because your code needs to run after the SmartClient `Init` servlet, but before anything else.

    If running outside of a servlet environment, you should invoke your config override code from the startup thread of the application, after the call to `Config.initGlobalConfig()` described in the class overview docs, but before any Config APIs are called.

    Parameters:
      `key` - The key of the property to set
      `value` - The new value for the property
    Returns:
      The property's old value, or null if it was not previously set

  - ### putAll

    public void putAll(Map map)
    Programmatically inject a set of values in a Map into the global config. See `put(Object, Object)` for important information about timing issues associated with this API.
    Parameters:
      `map` - A Map of property values to apply to the config